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Externally Supported Roofs

Externally supported roofs (ESR) are designed for higher pressure and higher vacuum applications and where heavy environmental or design loads are required.

Aquastore - Ethanol Fermenter - Sloped Steel Roof

CST provides many different steel roofs for storage tanks.


CST's Externally Supported Roof (ESR) is built to accommodate higher static and dynamic loads such as mixers and for applications with higher pressures and vacuum conditions.

Design and cost optimization has made CST's new ESR a high quality, highly competitive cover solution for the digester and other market's needs.

Variety of Materials

Externally supported roofs are predominantly manufactured in Vitrium glass-fused-to-steel, they can also be manufactured in stainless steel and epoxy coated. CST's engineers can match the customer's needs with the material and design to meet the application requirements.

Higher Loads

CST's ESR is specifically designed for applications where a center mixer or other center load is required to be carried by the roof. With a newly designed center ring, installation and service of center supported loads is easily accomplished.

Ease of Construction

When CST redesigned its ESR, higher performance was not the only result. The new ESR has approximately 30% fewer parts, which makes it even easier to assemble.

Cost Effectiveness

When higher loads, higher pressures and vacuums are required, CST's ESR is a cost-effective way to solve many cover challenges all at once. The new ESR's cost has been significantly reduced as a result of a recent redesign.

Unobstructed Internal Surface

CST's ESR is designed with a smooth, unobstructed inner surface. This smooth surface is ideal for applications where corrosion of internal structural members is a concern, maintenance of internal structural members is cost prohibitive and ease of cleaning is desirable.


CST's externally supported roofs are ideal for the following applications:

Industrial Liquids

ESR is well suited where the containment of a product requires a smooth inner surface on the roof for cleaning or contamination purpoes. Some chemical liquids may require higher pressures as well.

Anaerobic Digesters

An Anaerobic Digester may operate at higher pressures and vacuums necessitating the use of an ESR. Center mixers can also be accommodated by and ESR.